Extraction And Study Of Polypeptides From Cockroaches

Cockroaches,belonging to insects,have long lived on earth,and today have become a unique immune mechanism against external viruses and bacteria.At present,people often regard it as a pest,cockroaches have tenacious vitality and contain active polypeptides with medicinal functions in vivo,and the active polypeptides have the functions of inhibiting tumor cells,increasing the immunity of organisms,resisting bacteria and diminishing inflammation.People used to hate it,now human face up to its value,will become the darling of the medical and scientific research Provide experimental basis and basi for extracting natural active polypeptide and inhibiting tumor cells and increase immunity of organism by active polypeptide.This paper mainly studies the following contents:1.Optimization of the method for determining the polypeptide content in cockroach and the method for extracting the polypeptide.The content of polypeptide in cockroach polypeptide extract was determined by folin phenol method and biuret method.Cockroach polypeptides were extracted by heating reflux method,ultrasonic method and osmotic filtration method.The result showed that that content of polypeptide extract from cockroach was 25.58 %,26.13 %,31.24 % by biuret method,and 21.23 %,22.40 %,29.03 % by folin phenol method.compare the two methods,biuret method was better than folin phenol method.The content of cockroach polypeptide extracted by heating reflux method was 29.03 % and 31.24 %,that by osmotic filtration method was 22.40 % and 26.13 %,and that by ultrasonic apparatus was 21.23 % and 24.8 %,respectively the efficiency of cockroach polypeptide was higher than that of osmotic filtration method and ultrasonic instrument method.2.Study on the antitumor activity of cockroach polypeptide.The tumor model organisms of mouse sarcoma S180 and mouse hepatocarcinoma h22 were used in the laboratory.the weight of mice was observed by naked eye and recorded by table.the activity of cockroach polypeptide extract on tumor in mice was studied.The contents of cockroach polypeptide extracts were 20 mg / kg,40 mg / kg and 80 mg / kg,respectively.the inhibitory percentages of cockroach polypeptide extracts on S180 tumor-bearing mice were 23.16 %,34.97 %,65.15 % and 19.98 %,34.96 %,57.03 %,respectively.the results showed that cockroach polypeptide extracts effectively inhibited S180 and h22 tumor in mice.3.The effect of cockroach polypeptide extract on the immune system of mice.Mice injected with cyclophosphamide as the control group,according to the small,medium and large dose groups(20 mg / kg,40 mg / kg,80 mg / kg)were perfused,the spleen and thymus weight of mice were measured accurately,and the thymus index and spleen index were calculated.the results showed that cockroach active polypeptide solution could weaken the influence of cyclophosphamide(cyo)injection group on the number of t cells and b cells,and could significantly improve the ability of il-2(p < 0.001)in spleen cells of mice with low immunity.The polypeptide solution in cockroach extract can promote the proliferation of t cells and b cells in spleen of normal mice and induce interleukin-2 secretion in spleen cells of normal mice(p < 0.001).